Generally used in high-performance computing systems, Infiniband is a bidirectional point-to-point serial link often used to connect processors to storage devices and other high speed peripherals. Infiniband signals currently have a connection signal rate of 2.5 gigabit per second for single data rate (SDR), 5 gigabit per second for double data rate (DDR), and 10 gigabit per second for quad data rate (QDR), and are encoded with the industry standard 8B/10B encoding (every 10 bits sent carries 8 bits of data). Thus, Infiniband ports carry 2, 4, and 8 gigabits per second of useful data for, respectfully, single, double, and quad data rates.
The Infiniband architecture allows for the design of networking switches with single data rate, double data rate, and quad data rate ports. Ports are capable of detecting the capabilities of the attached devices and automatically switching between rates. Currently, when utilizing a higher data rate port at a lower rate, the entire port is consumed. This is inefficient, as the excess bandwidth within the switch cannot be utilized.